Billy Elliot v the badgers

A row over badgers has threatened plans to expand a world-famous London ballet school.

Ken Livingstone fears a scheme to rebuild the Royal Ballet School's base in Richmond Park could have a detrimental effect on wildlife.

The school is home to 126 young dancers and featured in the film Billy Elliot.

But Richmond Park, a national nature reserve, is one of the most important haunts for badgers in the capital, and a sett has been found within the boarding school grounds.

The Mayor fears this could be at risk if the school is allowed to grow in size by more than a third, newly

published planning documents reveal. The City Hall report states the potential threat to badgers and loss of 1,130 square metres of protected green space outweighs the educational benefits from an improved school. It reads: "Badgers are generally uncommon in London and their protection in this instance is a nature conservation issue."

The report adds that the sett in the school grounds is likely to be a refuge where the animals can escape " considerable persecution" in the park. It notes proposals would require the clearance of trees and vegetation around a sett, with construction taking place nearby.

The Mayor is now deciding whether to order Richmond council to refuse permission for the development, after councillors last week gave their unanimous backing for the scheme.

The council believes the redevelopment of the school's base - an 18th century grade I-listed mansion in the park known as White Lodge - would have city-wide benefits.

Richmond council chief Tony Arbour said the Mayor's intervention had come as a "bombshell" and threatened a widely popular proposal. He claimed the dispute over badgers had been resolved but said a sticking point remained over plans to build on protected parkland.

Mr Arbour said: "Richmond believes this is a proper use of White Lodge. The school is an enormous asset both for the borough and London."

White Lodge was completed in 1729 as a hunting lodge for George II and has been used by the ballet school since